JP3629124B2 - Semiconductor device cooling device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cooling device for a semiconductor element for conducting and dissipating heat generated from a semiconductor element to the outside and a method for manufacturing the same.
[0002]
[Prior art]
As a semiconductor element for high power, there are a GTO thyristor (gate turn off thyristor) and an IGBT (insulated gate bipolar transistor). These external shapes have a configuration in which external main electrodes are disposed at both ends of the insulator with a cylindrical insulator interposed therebetween. A liquid cooling type semiconductor device cooling device for efficiently dissipating heat generated during energization of the high power semiconductor element is disposed on the outer main surface of the external main electrode.
[0003]
FIG. 5 shows a planar configuration of the semiconductor element cooling apparatus 10, and FIG. 6 shows a cross-sectional configuration taken along line AA in FIG. 5.
[0004]
As shown in FIG. 6, the semiconductor element cooling device 10 includes a cooling block body 1 and a lid block 2 joined to the lower surface side of the cooling block body 1 and has a rectangular parallelepiped shape. As a material for the cooling block body 1 and the lid block 2, a copper material (tough pitch copper) is usually used from the viewpoint of thermal conductivity.
[0005]
The cooling block main body 1 has a structure having comb-like cooling fin portions 4a on one main surface. The cooling fin portion 4a is provided by forming a plurality of groove portions 4 having a predetermined depth in the cooling block main body 1 vertically and horizontally. The lid block 2 is formed in a rectangular flat plate shape corresponding to the cooling block body 1.
[0006]
And the cover block 2 is joined by brazing so that the opening side of the groove part 4 may be covered, and it has the structure where the cooling block main body 1 and the cover block 2 were sealed liquid-tightly. By adopting such a structure, the groove 4 constitutes a flow path for guiding a cooling liquid for cooling the cooling block main body 1 and the lid block 2. A brazing material 3 is interposed between the cooling block body 1 and the lid block 2.
[0007]
An inflow pipe 5 that leads to the groove 4 is connected to one side of the cooling block main body 1, and a discharge pipe 6 that leads to the groove 4 is connected to the other side of the cooling block main body 1. It is guided to the groove part 4 through the inflow pipe 5, and is configured to be discharged from the discharge pipe 6 after filling all the groove parts 4.
[0008]
As will be described later, since the surface opposite to the lid block 2 is a surface that is pressed against the semiconductor element, this is referred to as a pressed surface PS1.
[0009]
Here, FIG. 7 shows a state in which the semiconductor element cooling device 10 is attached to the semiconductor element. In FIG. 7, the GTO thyristor 11 is illustrated as a semiconductor element, and the semiconductor element cooling device 10 is disposed so that the pressure contact surface PS1 is in contact with the two external main electrodes 12 of the GTO thyristor 11, respectively.
[0010]
The element part which is the main body of the GTO thyristor 11 is disposed inside the insulating cylinder 13, and the two external main electrodes 12 are urged inward by pressure from the outside, and the internal main electrode provided in the element part is applied. It is configured to maintain electrical connection by pressure contact. The semiconductor element cooling device 10 is configured to be brought into pressure contact with the external main electrode 12 by the pressure from the outside, and to keep in contact with the semiconductor element cooling device 10.
[0011]
In this state, if a coolant is supplied to the semiconductor element cooling device 10 and the GTO thyristor 11 is energized, the heat generated during energization is conducted from the main surface of the external main electrode 12 to the cooling block body 1 and the lid block 2 side. And is radiated to the outside through the coolant.
[0012]
[Problems to be solved by the invention]
The conventional semiconductor device cooling apparatus 10 is configured as described above, but has the following two problems.
The first problem is that, as described above, in the semiconductor element cooling apparatus 10, the cooling block body 1 and the lid block 2 are joined by brazing as shown in FIG. In this type of brazing, silver brazing or the like is generally used as the brazing material 3.
[0013]
Accordingly, the melting temperature of the brazing material 3 at the time of brazing is about 600 to 800 ° C., and this heat is transferred to the copper cooling block body 1 and the lid block 2 and is deformed by the softening of the copper which is the material. It sometimes occurred.
[0014]
That is, in use, the GTO thyristor 11 is in a state in which pressure is applied from the outside and is maintained for a long period of time. As described above, the external pressure is also applied to the semiconductor element cooling device 10, and the semiconductor element cooling device 10 is kept in pressure contact with the external main electrode 12. The pressure from the outside becomes 9.8 × 10 ^{6 to} 14.7 × 10 ⁶ Pa (100 to 150 kgf / cm ² ), coupled with the softening of copper during brazing, The pressure contact surface PS1 is deformed, and the pressure contact force is uneven.
[0015]
Here, the deformation | transformation state of press-contact surface PS1 of the cooling block main body 1 is demonstrated using FIGS. 8-10. FIG. 8 is a plan view showing the pressure contact surface of the external main electrode 12 of the GTO thyristor 11 after maintaining the pressure contact state between the GTO thyristor 11 and the semiconductor element cooling device 10 for a long period of time. FIG. 9 is a sectional view taken along line BB in FIG.
[0016]
FIG. 10 is a cross-sectional view of the semiconductor device cooling apparatus 10 after maintaining the pressure contact state between the GTO thyristor 11 and the semiconductor element cooling apparatus 10 for a long period of time.
[0017]
As shown in FIG. 8, the press contact surface PS <b> 2 of the external main electrode 12 has an uneven pattern reflecting the shapes of the cooling fin portions 4 a and the groove portions 4 of the semiconductor element cooling device 10. This indicates that the external main electrode 12 is also heated in the brazing process in the element package process and is softened in the same manner as the cooling block body 1.
[0018]
As shown in FIG. 9, the concave portions 14 are formed corresponding to the cooling fin portions 4 a of the semiconductor element cooling device 10, and the convex portions 15 are formed corresponding to the groove portions 4, thereby forming an uneven pattern. .
[0019]
Further, as shown in FIG. 10, in the pressure contact surface PS1 of the semiconductor element cooling device 10, a convex portion 16 is formed corresponding to the cooling fin portion 4a, a concave portion 17 is formed corresponding to the groove portion 4, and the external A concave and convex pattern reversed from the pressure contact surface PS2 of the main electrode 12 is formed.
[0020]
As described above, the formation of uneven patterns on the pressure contact surfaces PS1 and PS2 of the semiconductor element cooling device 10 and the external main electrode 12 indicates that there is a difference in pressure contact force. However, there is a first problem that the GTO thyristor 11 is not sufficiently cooled to cause deterioration of element characteristics.
[0021]
In order to improve the non-uniformity of the pressure contact force, it is necessary to prevent the cooling block body 1 from being deformed. For this purpose, a method of increasing the thickness on the pressure contact surface PS1 side of the cooling block body 1, that is, the dimension t shown in FIG. However, this method has a problem that the cooling capacity of the semiconductor element cooling apparatus 10 is reduced.
[0022]
The second problem is that the cost of the flattening process of the pressure contact surface PS1 of the cooling block body 1 increases. In the flattening process, after the cooling block body 1 and the lid block 2 are joined by silver brazing, correction of parallelism defects due to warpage due to thermal strain generated during brazing or inclination due to the difference in thickness of the brazing material is corrected. In addition, this is an indispensable process for processing the surface roughness (flatness) within a specified value.
[0023]
In the case of a GTO thyristor, these specified values are flatness of about 5 to 10 μm and parallelism of about 20 to 50 μm. Conventionally, planarization has been performed by cutting or polishing with a lathe or a milling machine, so that a considerable amount of time is required for the processing and the manufacturing cost is increased.
[0024]
The present invention has been made to solve the above-described problems. The semiconductor element is uniformly pressed and can be efficiently cooled, and the electrical characteristics of the semiconductor element can be stabilized and the reliability can be improved. An object of the present invention is to provide a cooling device for a semiconductor element and a method for manufacturing the same, with reduced manufacturing costs.
[0025]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a cooling device for a semiconductor element, comprising: a first cooling block in which a flow path for a cooling fluid is formed on one main surface; A second cooling block joined by brazing so as to be sealed, and the other main surface opposite to the one main surface of the first cooling block is a main surface of the external main electrode of the semiconductor element In a cooling device for a semiconductor element that is pressed against and dissipates heat generated during energization of the semiconductor element to the outside, at least the main surface of the external main electrode of the semiconductor element on the other main surface of the first cooling block The surface hardness of the pressure contact surface to be pressure-contacted is in the range of HV = 70 to 90 in terms of Vickers hardness by the pressure molding process.
[0026]
According to a second aspect of the present invention, there is provided a method for manufacturing a cooling device for a semiconductor element, wherein the semiconductor element is in pressure contact with a main surface of an external main electrode of the semiconductor element and dissipates heat generated during energization of the semiconductor element to the outside. A method of manufacturing a cooling device, the step (a) of preparing a first cooling block in which a flow path for cooling fluid is formed on one main surface, and covering the one main surface and making the flow channel liquid-tight A step (b) of joining the second cooling block by brazing so that the first and second cooling blocks are joined to each other, and mounting the joined first and second cooling blocks on a pressure molding die. By press-molding the cooling block of 2, the pressure contact surface of the other main surface opposite to the one main surface of the first cooling block is pressed to at least the main surface of the external main electrode of the semiconductor element. Surface hardness in the range of HV = 70-90 in Vickers hardness And a step (c) to.
[0027]
According to a third aspect of the present invention, there is provided the method for manufacturing a cooling device for a semiconductor element, wherein the first and second cooling blocks are made of copper, aluminum, or an alloy thereof, The pressure is in the range of 4.9 × 10 ^{7 to} 9.8 × 10 ⁷ Pa (500 to 1000 kgf / cm ² ).
[0028]
According to a fourth aspect of the present invention, there is provided the method for manufacturing a cooling device for a semiconductor element, wherein the press-molding mold is a bottomed and uncovered box-shaped lower mold that houses the first and second cooling blocks. And an upper mold that is inserted from the upper opening of the lower mold and presses the first and second cooling blocks, and the tip of the upper mold that presses the other main surface is The flatness is 5 μm or less, and the step (c) includes a step of pressure-molding the first and second cooling blocks and simultaneously setting the flatness of the other main surface to 5 μm or less.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
<Embodiment>
<Device configuration>
As an embodiment according to the present invention, FIG. 1 shows a plan configuration of a semiconductor element cooling apparatus 10A, and FIG. 2 shows a cross-sectional configuration along line AA in FIG.
[0030]
As shown in FIG. 2, the semiconductor device cooling device 10A includes a cooling block main body 1A (first cooling block), and a lid block 2A (second cooling block) joined to the lower surface side of the cooling block main body 1A. It has a rectangular parallelepiped shape. As the material of the cooling block main body 1A and the lid block 2A, either copper, aluminum, or an alloy thereof is used, but generally a copper material (tough pitch copper) is used from the viewpoint of thermal conductivity. ing.
[0031]
The cooling block body 1A has a structure having comb-like cooling fin portions 4a on one main surface. The cooling fin portion 4a is provided by forming a plurality of groove portions 4 having a predetermined depth vertically and horizontally in the cooling block main body 1A.
[0032]
The lid block 2A is formed in a rectangular flat plate shape corresponding to the cooling block main body 1A. The lid block 2A is joined by brazing so as to cover the opening side of the groove portion 4, and the cooling block main body 1A and the lid block 2A are sealed in a liquid-tight manner. By setting it as such a structure, the groove part 4 comprises the flow path which guides the cooling fluid for cooling the cooling block main body 1A and the lid block 2A. A brazing material 3 is interposed between the cooling block main body 1A and the lid block 2A.
[0033]
A concave region having a rectangular shape in plan view is formed on the main surface opposite to the main surface to which the lid block 2A is bonded, and this is pressed against the semiconductor element as will be described later. It becomes the pressure contact surface PS3. The surface hardness of the pressure contact surface PS3 is about HV = 70 to 90 in terms of Vickers hardness.
[0034]
In addition, although a concave region also exists on the outer main surface of the lid block 2A, this is called a pressure surface AS because it is a surface to which pressure from the outside described later is applied.
[0035]
As shown in FIG. 1, an inflow pipe 5 leading to the groove 4 is connected to one side of the cooling block main body 1A, and a discharge pipe 6 leading to the groove 4 is connected to the other side of the cooling block main body 1A. The cooling liquid is guided to the groove part 4 through the inflow pipe 5, and after all the groove parts 4 are filled, the cooling liquid is discharged from the discharge pipe 6.
[0036]
Here, FIG. 3 shows a state in which the semiconductor element cooling device 10A is attached to the semiconductor element. In FIG. 3, a disk-shaped GTO thyristor 11 is illustrated as a semiconductor element, and the pressure contact surfaces PS3 of the semiconductor element cooling device 10A are in contact with the pressure contact surfaces PS2 of the two external main electrodes 12 of the GTO thyristor 11, respectively. As described above, the semiconductor element cooling device 10A is arranged.
[0037]
The element part which is the main body of the GTO thyristor 11 is arranged inside the insulating cylinder 13 and urges the two disk-shaped external main electrodes 12 inward by pressure from the outside to provide an internal part provided in the element part. The electrical connection is maintained by pressing the main electrode. The semiconductor element cooling device 10 </ b> A is also in pressure contact with the external main electrode 12 by this external pressure, and is configured to maintain contact between the semiconductor element cooling device 10 </ b> A and the external main electrode 12.
[0038]
Here, the pressure applied from the outside is 9.8 × 10 ^{6 to} 14.7 × 10 ⁶ Pa (100 to 150 kgf / cm ² ), but the surface hardness of the pressure contact surface PS3 is a curing treatment as described later. By carrying out, since it is set to about HV = 70-90 by the Vickers hardness, the situation where the press-contact surface PS3 deform | transforms by press-contact is prevented. Therefore, when the GTO thyristor 11 is used, even when the externally applied pressure state is maintained for a long period of time, the semiconductor element cooling device 10A and the external main electrode 12 have the pressure contact surfaces PS3 and PS2. The concave / convex pattern is not formed, and the pressure contact force is uniformly applied to the pressure contact surface PS2 of the external main electrode 12, and the GTO thyristor 11 is sufficiently cooled, so that the device characteristics are not deteriorated.
[0039]
<Manufacturing method>
Here, a manufacturing method of the semiconductor device cooling apparatus 10A described above will be described.
First, a cooling block body 1A having comb-like cooling fin portions 4a on one main surface is formed. The cooling fin portion 4a is obtained by cutting a block material made of copper or aluminum having good thermal conductivity to form a plurality of groove portions 4 having a predetermined depth vertically and horizontally. In this embodiment, an example in which copper is used will be described. The cooling block body 1A may be formed by forging.
[0040]
Next, a rectangular flat lid block 2A corresponding to the cooling block main body 1A is prepared, the brazing material 3 is sandwiched between the cooling block main body 1A and the lid block 2A and heated to melt the brazing material 3. Then, the cooling block body 1A and the lid block 2A are joined in a liquid-tight manner.
[0041]
Next, as shown in FIG. 4, the joined cooling block body 1 </ b> A and lid block 2 </ b> A are set in a pressure molding die 20.
[0042]
Here, the configuration of the pressure molding die 20 will be described. The pressure molding die 20 is inserted from the bottomed and uncovered box-shaped lower die 21 that accommodates the cooling block main body 1A and the lid block 2A, and the upper opening of the lower die 21, and the cooling block main body 1A and The upper mold 22 is configured to press the lid block 2A.
[0043]
The internal shape of the lower mold 21 is a shape that substantially matches the contour shape of the cooling block main body 1A and the lid block 2A, and the cooling block main body 1A and the lid block 2A are arranged so that the lid block 2A is positioned on the bottom side. .
[0044]
An escape groove 23 is formed at the corner of the bottom of the lower mold 21, and when the cooling block main body 1A and the lid block 2A are inserted, it functions as an air vent and can be smoothly inserted.
[0045]
The tip part TP of the upper mold 22 is a convex part, and a gap is formed between the upper mold 22 and the inner wall of the upper mold 22. The passing dimension is larger than the diameter of the external main electrode 12 of the GTO thyristor 11. Then, if the planar view contour shape of the tip portion of the upper mold 22 is a rectangular shape similar to the cooling block main body 1A, a pressure contact surface PS3 having a rectangular planar view contour shape is formed as shown in FIG. Will be. Note that the contour shape in plan view of the tip portion of the upper mold 22 may be a circular shape having a diameter larger than the diameter of the external main electrode 12 of the GTO thyristor 11.
[0046]
Further, the flatness of the tip portion TP of the upper mold 22 is 5 μm or less, and the parallelism of the upper mold 22 and the lower mold 21 is 20 μm or less.
[0047]
Here, it returns to description of a manufacturing process. The bonded cooling block main body 1A and lid block 2A are set in the pressure molding die 20 as described above, and the upper die 22 is lowered as indicated by an arrow in the drawing, and the pressure is 4.9 ×. When 10 ⁷ Pa to 9.8 × 10 ⁷ Pa (500 to 1000 kgf / cm ² ) is added, the surface of the cooling block main body 1A with which the tip TP of the upper mold 22 comes into contact is depressed, and the concave pressure contact surface PS3 is formed. Thus, the semiconductor device cooling apparatus 10A is completed.
[0048]
By this pressure forming process, the cooling block main body 1A and the lid block 2A softened due to the brazing process are plastically changed, and the surface hardness is about HV = 70 to 90 in terms of Vickers hardness. The surface hardness in the softened state is about HV = 40-60 in terms of Vickers hardness, and the Vickers hardness of copper (tough pitch copper) before softening is about HV = 90-100, It almost recovered to the hardness before softening.
[0049]
In this way, by increasing the surface hardness of the pressure contact surface PS3 of the cooling block main body 1A, it is possible to prevent the pressure contact surface PS3 from being deformed by pressure welding, so the thickness on the pressure contact surface PS3 side of the cooling block main body 1A, that is, FIG. It is not necessary to increase the dimension t shown in FIG. 2, and it is possible to reduce the thickness t by increasing the surface hardness. If the dimension t is reduced, the conduction thermal resistance is reduced in proportion thereto, and the cooling capacity of the semiconductor element cooling device 10A is improved. In addition, when performing pressure molding, the dimension t can also be set to about 5 mm.
[0050]
Further, the flatness of the tip portion TP of the upper mold 22 is set to 5 μm or less, and the parallelism of the upper mold 22 and the lower mold 21 is set to 20 μm or less, so that the flatness of the pressure contact surface PS3 of the cooling block body 1A is set. Is 5 μm or less and the parallelism is 20 μm or less, and the planarization step is performed simultaneously with the pressure forming step. Therefore, a planarization process that requires cutting or polishing with a lathe or a milling machine as in the prior art becomes unnecessary, and the manufacturing time can be reduced by shortening the processing time.
[0051]
In addition, since the relief groove 23 is formed in the corner | angular part of the bottom part of the lower metal mold | die 21, the concave pressing surface AS is formed in the outer main surface of the lid block 2A by a press molding process. Although this surface is not required to have flatness or parallelism as much as the pressure contact surface PS3 of the cooling block main body 1A, the processing accuracy of the pressure molding die 20 is set high as described above, so that it conforms to the pressure contact surface PS3. Flatness and parallelism can be obtained.
[0052]
<Modification>
In the semiconductor element cooling device 10A described above, the tip portion TP of the upper mold 22 is a convex portion, and an example in which a gap is formed between the inner wall of the upper mold 22 is shown. However, this is used as a refuge for compressive force when the cooling block main body 1A is compressed by pressurization, and as a result, the pressure contact surface PS3 is concave.
[0053]
However, the pressure contact surface PS3 does not have a concave shape if the escape dimension of the compression force is not formed and the passing dimension of the tip portion TP of the upper mold 22 is made substantially the same as the dimension of the cooling block body 1A.
[0054]
Moreover, although the escape groove 23 is formed in the corner | angular part of the bottom part of the lower metal mold | die 21, this is not necessarily required and can also be abbreviate | omitted, In that case, pressurization surface AS does not become concave shape.
[0055]
In addition, the cooling block body 1A has a structure having the comb-like cooling fin portions 4a. However, this structure is not limited to the comb-tooth shape. Similar effects can be obtained by applying the invention.
[0056]
【The invention's effect】
According to the semiconductor device cooling device of the first aspect of the present invention, the first cooling block and the second cooling block are joined by brazing, and their surfaces are softened by heating at the time of brazing. Even in such a case, the surface hardness of the pressure contact surface of the other main surface of the first cooling block, which is in pressure contact with at least the main surface of the external main electrode of the semiconductor element, is HV in terms of Vickers hardness by the pressure forming process. = 70 to 90, so that the pressure pressed against the main surface of the external main electrode of the semiconductor element is, for example, 9.8 × 10 ^{6 to} 14.7 × 10 ⁶ Pa (100 to 150 kgf / cm ² ). However, the situation where the pressure contact surface is deformed by pressure contact is prevented. Therefore, when the semiconductor element is used, even when the externally applied pressure is maintained for a long period of time, the uneven pattern reflecting the shape of the flow path for the cooling fluid is a cooling device for a semiconductor element. The semiconductor element cooling device is uniformly pressed against the external main electrode, the semiconductor element is reliably cooled, and deterioration of element characteristics is prevented.
[0057]
According to the method for manufacturing a cooling device for a semiconductor element according to claim 2 of the present invention, a manufacturing method suitable for the cooling device for a semiconductor element according to claim 1 is obtained.
[0058]
According to the method for manufacturing a cooling device for a semiconductor element according to claim 3, when the material of the first and second cooling blocks is either copper, aluminum, or an alloy thereof, The surface hardness of the surface can be set to HV = 70 to 90 in terms of Vickers hardness.
[0059]
According to the method for manufacturing a cooling device for a semiconductor element according to claim 4 of the present invention, the flatness of the other main surface, that is, the pressure contact surface is set to 5 μm or less simultaneously with the pressure molding of the first and second cooling blocks. Therefore, the flatness required for the cooling device for semiconductor elements can be satisfied.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a planar configuration of a cooling device for a semiconductor element according to the present invention.
FIG. 2 is a diagram illustrating a cross-sectional configuration of a semiconductor element cooling device according to the present invention.
FIG. 3 is a view showing a state in which the cooling device for a semiconductor element according to the present invention is attached to the semiconductor element.
FIG. 4 is a diagram illustrating a manufacturing process of a semiconductor device cooling device according to the present invention.
FIG. 5 is a diagram illustrating a planar configuration of a conventional cooling device for a semiconductor element.
FIG. 6 is a diagram illustrating a cross-sectional configuration of a conventional cooling device for a semiconductor element.
FIG. 7 is a diagram showing a state in which a conventional cooling device for a semiconductor element is attached to a semiconductor element.
FIG. 8 is a diagram for explaining a problem of a conventional cooling device for a semiconductor element.
FIG. 9 is a diagram illustrating a problem of a conventional cooling device for a semiconductor element.
FIG. 10 is a diagram illustrating a problem of a conventional cooling device for a semiconductor element.
[Explanation of symbols]
1A cooling block body (first cooling block), 2A lid block (second cooling block), 3 brazing material, PS3 pressure contact surface, 11 GTO thyristor (semiconductor element), 12 external main electrode, 20 pressure molding gold Mold, 21 Lower mold, 22 Upper mold, TP tip.

Claims (4)

A first cooling block in which a flow path for cooling fluid is formed on one main surface, and a second cooling block that covers the one main surface and is joined by brazing so as to seal the flow path in a liquid-tight manner. And
A semiconductor element that dissipates heat generated during energization of the semiconductor element, with the other main surface opposite to the one main surface of the first cooling block being in pressure contact with the main surface of the external main electrode of the semiconductor element Cooling equipment for
The surface hardness of the pressure contact surface of at least the main surface of the external main electrode of the semiconductor element on the other main surface of the first cooling block is in the range of HV = 70 to 90 in terms of Vickers hardness by pressure molding. A cooling device for a semiconductor element, characterized in that A method of manufacturing a cooling device for a semiconductor element that is pressed against a main surface of an external main electrode of a semiconductor element and dissipates heat generated during energization of the semiconductor element to the outside,
(A) preparing a first cooling block in which a flow path for cooling fluid is formed on one main surface;
(B) joining the second cooling block by brazing so as to cover the one main surface and seal the flow path in a liquid-tight manner;
(C) The first and second cooling blocks that have been joined are mounted on a pressure molding die, and the first and second cooling blocks are pressure-molded. And a step of setting the surface hardness of at least the pressure contact surface of the other main surface opposite to the main surface to be in pressure contact with the main surface of the external main electrode of the semiconductor element in a range of HV = 70 to 90 in terms of Vickers hardness. The manufacturing method of the cooling device for semiconductor elements. The material of the first and second cooling blocks is copper, aluminum, or an alloy thereof,
3. The method for manufacturing a cooling device for a semiconductor element according to claim 2, wherein the predetermined pressure is a pressure in a range of 4.9 × 10 ^{7 to} 9.8 × 10 ⁷ Pa (500 to 1000 kgf / cm ² ). The pressure molding die is
A bottomed and uncovered box-shaped lower mold for housing the first and second cooling blocks;
An upper mold that is inserted from the upper opening of the lower mold and presses the first and second cooling blocks;
The tip of the upper mold that presses the other main surface has a flatness of 5 μm or less,
The step (c)
The manufacturing method of the cooling device for a semiconductor element according to claim 3, comprising a step of pressing and molding the first and second cooling blocks and simultaneously setting the flatness of the other main surface to 5 μm or less.

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